This invention relates to couplings
The invention is more particularly concerned with couplings for fitting onto corrugated tubing, conduits or other corrugated members.
There are several different forms of existing couplings which can be fitted onto corrugated tubing. These make use of teeth or other surface formations that, when pushed inwards, engage between corrugations on the tubing and lock it on the coupling. One such coupling is described in GB 2123106. This has teeth which are deformed inwardly when an outer collar is pushed axially onto the coupling. GB 2125501 describes a similar coupling in which the collar is held in position by means of bayonet fitting. A coupling is also sold by PMA Elektro A. G. which has a separate U-shape locking piece that is pushed into a slot in the body of the coupling so that it lies between the corrugations on the tubing.
These previous couplings have the disadvantage that the coupling is locked by putting together two separate parts. This means that the parts of the coupling are separate until locked, increasing the risk that parts will become lost either during initial installation or when subsequently removed.